Now to that nightmare at the amusement park just outside of dallas. A family watching as a mother 14 stories high falls to her death. Tonight, how could this happen? And what are the most dangerous rides in the america? Abc's clayton sandell is in arlington, texas. Reporter: At six flags over texas the coasters are king. But today, in one corner of the amusement park, the texas giant is quiet. Shut down friday night after a woman fell to her death. She goes up, like this, and then when it drops to come down that's when it released and she just stumbled. The daughter and son-in-law, yelling and screaming, my mother has fallen off. Reporter: A witness tells the dallas morning news she saw the woman get on the ride. She said that the woman appeared concerned that her safety harness wasn't secured. Six flags said in a statement, we are committed to determining the cause of this tragic accident. Two years ago, the texas giant stranded riders 14 stories above the ground. Safety advocates say this latest accident highlights the patchwork of state laws governing roller coaster operators. We need the same standards, the same inspection guidelines applied to all amusement rides in every state. Reporter: Statistically, experts say, that amusement parks are safe. A trade group estimates that the chance of being injured 1 in 24 million. When it comes to emergency room visits twice as many people are injured on the carousel compared to roller coasters. And you can see the texas giant right over my shoulder here, david. We're told this roller coaster is shut down indefinitely.

This transcript has been automatically generated and may not be 100% accurate.

Now Playing: Video Released in Police-Involved Shooting That Left Driver Paralyzed

{"id":19724995,"title":"Mother Falls to Death From Amusement Park Ride","duration":"1:47","description":"Children, passengers watch in horror as mother falls off 14-story high roller coaster.","url":"/WNT/video/mother-falls-death-amusement-park-ride-19724995","section":"WNT","mediaType":"default"}